This application responds to the AHRQ K18 (Mentored Career Enhancement Award in Patient Centered Outcomes Research, PCOR) for mid-career investigators. Andrew M Naidech, MD MSPH has a track record of expertise in neurovascular and stroke outcomes research and intends to transition to an independent career in PCOR. The proposal includes formal education in PCOR and comparative effectiveness research that complements his biostatistics training, and utilizes the AHRQ-funded K12 NU- PATIENT program. Candidate. Dr. Naidech is a vascular neurologist and neurointensivist with formal biostatistics training and a track record of outcomes-based clinical research in hemorrhagic stroke, the proposed topic of study. He founded the Northwestern University Brain Attack Registry (NUBAR), which has enrolled nearly 400 patients with ICH. NUBAR data have had to >40 publications since 2009, attesting to continued productivity. Dr. Naidech has enfolded quality of life outcomes into NUBAR since 2011, creating a rich dataset for comparative effectiveness research. Education. The primary mentor is Jane Holl, MD, MPH, a noted AHRQ-supported researcher and Director of the Center for Education in Health Sciences at Northwestern. The PCOR mentor is David Cella, PhD, PI of the NU-PATIENT educational program, the NIH Patient Reported Outcomes Measurement Information System (PROMIS) Statistical Center, and Neuro-QOL. The comparative effectiveness research mentor is Larry Hedges, PhD, Director of the Institute for Policy Research and Chair of Biostatistics at Northwestern. Environment. Northwestern is a national leader in PCOR. PROMIS and Neuro-QOL were partially developed at Northwestern under Dr. Cella's leadership with NIH funding. PROMIS and Neuro-QOL outcomes have been captured for patients enrolled in NUBAR since 2011. The newly available Chicago Area Patient Centered Outcomes Research Network (CAPriCORN, a PCORI Clinical Data Research Network) retrieves data from multiple area healthcare organization on rehospitalization, medications, and will provide multi-center data for this proposal. Research. This two-year intensive experience takes advantage of existing data collected by NUBAR and CAPriCORN. In this proposal we will examine the impact of prophylactic seizure medications on rehospitalization from both NUBAR and CAPriCORN, and health-related quality of life data obtained with state- of-the-art PROMIS and Neuro-QOL methods for patients enrolled in NUBAR. This research and training will lead to future independence with the Patient Centered Outcomes Research Institute (PCORI), AHRQ and NIH utilizing comparative effectiveness research methods to improve patient-centered outcomes.